规范反应谱长周期部分修正方法的探讨

为将反应谱方法应用于长周期大跨度桥梁结构的抗震设计,本文探讨了对现有公路工程抗震设计规范中地震反应谱的长周期段进行修正的方法.数字化强震记录反应谱的计算结果表明,地震动水平分量的位移反应谱可以有一个明显的峰点.同时当周期无限长时,地震动相对位移反应谱应等于地面运动位移最大值.以此为基础,增加了表达长周期地震动反应谱特性的参数.经过修正和补充的规范化反应谱可用于长周期大跨度桥梁结构的抗震设计.

MODIFICATION OF CODE RESPONSE SPECTRUM IN LONG PERIOD PHASE

This paper discusses the problem of use of the response spectrum method in seismic designs of long-span bridges and the modification of the expression of response spectrum in the design code The response spectra calculated from digital records of strong earthquake show that the seismic response spectra of horizontal components may have signaficent peaks. Meanwhile, the relative displacement response spectrum should equal to the maximum of displacement of seismic ground motion in case the period is infinitely long. The code expression of seismic response spectrum has been modified to meet the above two rules. Parameters that control the response spectrum in long-period phase are introduced. The modified code response spectrum can be used in seismic designs of long - span bridges.